Theory of Mind in High-Functioning Autism and Asperger Syndrome

The aim in this thesis was to extend research on theory of mind (ToM) development in children with autism spectrum disorders (including high-functioning autism and Asperger syndrome) through three key areas. First, the candidate sought to investigate the link between ToM and social skills in a novel manner. Second, the candidate sought to further investigate the link between ToM and language and to compare groups with high-functioning autism (HFA) versus Asperger syndrome (AS) in this respect. Specifically, the impact of vocabulary and grammar on ToM test performance in each diagnostic group was investigated. Third, the candidate sought to investigate whether impairments in ToM may be amenable to change. This was investigated via a training study designed to teach children with an ASD (who failed the false belief test at pretest) to understand beliefs via cartoon thought bubbles. A total of 118 children (41 with HFA, 44 with AS, three with Pervasive Developmental Disorder- Not Otherwise Specified, and 30 age-matched typically developing children) between the ages of four and 12 years were tested over four studies. In Study 1 the correlations between ToM and social skills on a newly developed scale (Peterson, Slaughter, & Paynter, 2007) as rated by teachers were investigated, while Study 2 used parent ratings. The links between ToM and language (grammar and vocabulary) were investigated in Study 3. Study 4 was a training study of ToM via thought bubbles, extending upon Wellman et al. (2002). Impairments in ToM were found in children with HFA across studies. Their false belief test performance was consistently significantly poorer than both typically developing children and children with AS. In contrast, children with AS demonstrated relatively spared ToM abilities (at least by an average age of eight). Indeed, they performed similarly on ToM tasks to their chronological and verbal mental age and general intellectual ability-matched typically developing peers. The relationship between ToM and social skills for each group was found to differ depending on the rater. Positive correlations were observed for the HFA group with teacher ratings, but not parent ratings, which were non-significant, consistent with earlier studies (e.g. Hughes, Soares-Boucaud, Hochmann, & Frith, 1997) using a different social skills measure. In contrast, positive correlations were observed for the AS group with parent ratings, but not teacher ratings, which were non-significant. Language, in particular grammar, appeared to be especially important for task success in children with AS. In contrast, a more general language factor appeared to be important for HFA. Training children with ASD in ToM using thought bubbles was significantly effective and showed some generalisation beyond the trained false belief task. Theoretical discussion of these findings, potential practical applications, and challenges for future research conclude this thesis